do you know The Ultimate Machine ?
good for winter.
Here are some DIY instructions: http://www.instructables.com/id/The-Most-Useless-Machine/
Thats hilarious! 
Bad arm!
I think this alternative version would be cool:
Basically have a motion sensor in the vicinity of the switch.
So that when you tried to turn it off,
the hand comes out and *SLAPS* yours!
Hehehe. Would be a great party trick.
You’d need a fairly fast spring/motor though…